Efficacy of cap-assisted colonoscopy in comparison with regular colonoscopy: a randomized controlled trial

Colonoscopy cannot be completed in up to 10% of cases. We postulate that cap-assisted colonoscopy (CAC), by fitting a mucosectomy cap to the tip of a colonoscope, could improve the outcome.

We conducted a prospective randomized controlled trial in two regional endoscopy centers. All colonoscopies were performed by experienced colonoscopists. Patients 18 years or older undergoing their first colonoscopy were recruited. Patients were randomized to the CAC group or to the regular colonoscopy (RC) group. The first successful cecal intubation rate, rescue cecal intubation rate, cecal intubation and total colonoscopy times, and polyp detection rate were compared.

One thousand patients were enrolled (mean age 52.6 years, 46% men). There was no statistically significant difference in the first successful cecal intubation rate between CAC and RC groups (96.2% vs. 94.6%, P=0.23). The cecal intubation and total colonoscopy times were shorter in the CAC group than in the RC group (6.0+/-4.0 min vs. 7.2+/-4.8 min, P<0.001; 14.7+/-8.6 min vs. 16.7+/-10.3 min, P=0.001). The adenoma detection rate was significantly lower in the CAC group than in the RC group (30.5% vs. 37.5%, P=0.018), but there was no significant difference in the detection of advanced lesions. In case of failing cecal intubation, use of CAC as a rescue method could achieve a higher success rate than RC (66.7% vs. 21.1%, P=0.003).

Among experienced colonoscopists, CAC did not improve the initial cecal intubation rate and had a lower adenoma detection rate. However, it shortened the cecal intubation time and performed better as a rescue method. Its utilization should be reserved for selected cases, especially when initial cecal intubation fails.